# POST /readability: $0.002 per call

Readability of English text or a web page/PDF: Flesch reading ease, Flesch-Kincaid grade, Gunning fog, SMOG, Coleman-Liau and ARI scores, a plain-words level, word and sentence counts, reading time, and what to fix: the longest sentences, long words and passive phrases. Pure code, no AI: the same text always scores the same.

- **Price:** $0.002 in USDC, the same on Base, Solana, Polygon, Arbitrum. Failed calls are never charged.
- **Free trial:** yes, 20 free calls a day from Claude, Cursor or any MCP client ([set-up](/mcp/setup)).
- **Tier:** live
- **Answers cached for:** 1 day(s)
- **Data sources:** our own code (standard readability formulas); our /markdown reader for URLs
- **Lane:** AI tools ([OpenAPI](/openapi/ai.json))
- **Live health:** [status page](/status)

## Free sample

See an answer for the demo input first, free (no payment, 10 a minute): [https://aayatai.com/sample/readability](/sample/readability). It is a stored real answer when we have one, otherwise an example marked `"kind": "illustrative"`.

```bash
curl "https://aayatai.com/sample/readability"
```

## 1. See the price (free)

Call it without paying: you get `402 Payment Required` and a `PAYMENT-REQUIRED` header with the exact price and where to pay.

```bash
curl -i -X POST https://aayatai.com/readability -H "content-type: application/json" -d '{"text":"The cat sat on the mat. It was a sunny day, and the children were playing happily in the garden behind the house."}'
```

## 2. Pay and call (TypeScript)

```bash
npm install @x402/fetch @x402/evm viem
```

```ts
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

// A wallet used only by your agent, holding a little USDC on Base.
const account = privateKeyToAccount(process.env.WALLET_PRIVATE_KEY as `0x${string}`);
const pay = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }],
});

const res = await pay("https://aayatai.com/readability", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({"text":"The cat sat on the mat. It was a sunny day, and the children were playing happily in the garden behind the house."}),
});
console.log(await res.json());
```

## 3. Or as an MCP tool

```ts
// MCP server: https://aayatai.com/mcp (Streamable HTTP). With the x402 MCP client (see /start):
const result = await client.callTool("readability", {"text":"The cat sat on the mat. It was a sunny day, and the children were playing happily in the garden behind the house."});
```

## Inputs

- `text` (string): The text to score (use this or url).
- `url` (string): A web page or document to score (use this or text).

Bad inputs are rejected with HTTP 400 before any payment is asked for.

## Example answer

Example only: the shape of an answer, with placeholder addresses and made-up figures. It is not data about any real token or wallet; call the service (or its free sample) for real results.

```json
{
  "level": "very easy (age 11 and under)",
  "scores": {
    "fleschReadingEase": 84.8,
    "fleschKincaidGrade": 4.3,
    "gunningFog": 6.3,
    "smog": 7.2,
    "colemanLiau": 4.1,
    "automatedReadability": 2.3
  },
  "counts": {
    "sentences": 2,
    "words": 23,
    "syllables": 30,
    "complexWords": 1,
    "averageWordsPerSentence": 11.5,
    "readingTimeMinutes": 0.1
  },
  "suggestions": {
    "longSentences": [],
    "longWords": [],
    "passivePhrases": []
  },
  "source": {
    "chars": 113,
    "truncated": false
  }
}
```

## Related

- [POST /invoice/parse](/services/invoice-parse) ($0.02): Parse an invoice or receipt into clean JSON: supplier, VAT/tax ID, invoice number, dates, currency, line items, subtotal, tax, total, amount due and bank detail
- [POST /document/ask](/services/document-ask) ($0.02): Ask a question about one document (PDF, Word, web page or pasted text) and get a short answer with the exact quotes that support it.
- [POST /entities](/services/entities) ($0.005): Named-entity extraction: the organisations, people, places, products, events, dates, amounts of money and laws in a text or document (URL to a page or PDF), wit
- [POST /keywords](/services/keywords) ($0.003): Key phrases and topics of a text, web page or PDF, for tagging, SEO and search indexes: up to 30 key phrases, most important first, each checked by code to real
- [POST /moderate](/services/moderate) ($0.005): Content moderation for AI agents and apps: is this text safe?
- [POST /pii/redact](/services/pii-redact) ($0.005): Remove personal data from text before an agent stores it or sends it to another model: emails, phone numbers, card numbers, IBANs, NI numbers, SSNs, IP addresse
- [POST /sentiment](/services/sentiment) ($0.005): Sentiment analysis for reviews, comments, support tickets and social replies: up to 50 texts per call, each labelled positive, neutral, negative or mixed with a
- [POST /text/cluster](/services/text-cluster) ($0.01): Group similar texts: send up to 200 pieces of feedback, support tickets, reviews or survey answers and get back the groups that say much the same thing, biggest

New here? [Getting started in 60 seconds](/start). All services: [Aayat AI](/).